Introduction: This experiment was to introduce the methods and capability of a
microscope. Learning how to adjust the microscope to focus on small objects is
one of the many things I have learned from this activity. In this activity, our
group would prepare slides of cheek cells, pond microorganisms, newspaper
clippings, and potato cells in order to take a closer look at them. We would first
make the slides themselves, and then place them under the microscope.
Depending on the different “specimens” we would look at different
magnifications to determine what each one looked like up close.
Parts
Eyepiece
Arm
Stage Controls
Coarse Focus
Fine Focus
Objective Lenses
1000x Objective
Mechanical Stage
Iris Diaphragm
Illuminator
Functions
Used to look through, focuses light
from objective into the eye
Supports the tube and attaches the top
of the microscope to the base
Moves the already placed slide that is
on the mechanical stage with special
knobs, replaces the need for hands to
physically adjust the slide to fit under
the objective lenses
Focusing mainly for low magnifications
For focusing mainly for high
magnifications
Usually consisted of 4x, 10x, and 100x
lenses, are usually coupled with a 10x
eyepiece, shortest lenses used for
lowest power, longer lenses for higher
power,
Highest power of lenses, usually
requires a lot of fine focusing, shows
extremely magnified images to the eye
The platform in which the slide or
object is placed on to be viewed under
the objective lenses.
Controls the amount of light passing
through the lenses
Light source that beams up to show the
image and pass to the eye
6. Through the eyepiece, the letter “e” looks a lot more detailed and much larger,
compared to what I see on the stage.
7. If I move the stage to the upper right area, the image moves to the lower left
corner if I am looking through the eyepiece.
8. Moving the slide to the lower left side, the image through the eyepiece moves
to the upper right corner.
9. Changing the light intensity to go lower makes the letter “e’s” background
grow darker in color. When I increase the light intensity, the background
becomes much more lighter.
It seems that the pond scum are actually consuming the dirt particles. This is
probably why they seem to be always clustered around dirt “mounds” or a
concentration of dirt particles. I believe these organisms are a vital part of any
ecosystem, always cleaning and consuming the waste.
LOW POWER
Eyepiece Magnification
10
HIGH POWER
Eyepiece Magnification
10
(X)
Objective Magnification
4
=
Total Magnification
40 X
(X)
Objective Magnification
40
=
Total Magnification
400 X
The total magnification of a compound microscope can be found by multiplying the
eyepiece magnification with the objective magnification.
Conclusion Questions:
1.
a. Carefully hold the microscope with two hands
i. One hand holding the arm
ii. One hand under the base
b. Plug in the electric plug safely, and make sure its not around water
2. This light microscope is considered a compound microscope is due to the
amount of lenses it has. Since there are more than two lenses, this light
microscope is considered to be a compound light microscope.
3. The images are inverted due to the lenses acting against our eyes. The
lenses and the light make the image reach the eyepiece inverted. Since the
eyepiece itself does not invert the image, acting as a simple magnifier, the
image reaches our eyes inverted.
4. If the specimen is not centered on low power, then when going to a higher
power the specimen will be nowhere near where the objective is focused
on. This is due to the higher the objective power, the fraction of the total
slide we are viewing becomes smaller and smaller.
5.
a.
Eyepiece Magnification
20
(X)
Objective Magnification
10
=
Total Magnification
200 X
(X)
Objective Magnification
43
=
Total Magnification
860 X
b.
Eyepiece Magnification
20
6. In order to make a proper wet mount of the letter “e” one would first need
to cut a small “e” from a printed-paper. After doing so place the “e” on a
glass slide and add one drop of water on the “e.” Slowly put a cover slide
on, place it from the side in order to lessen the likelihood of air bubbles.
7. Going from low to high power, the light seems to dim a lot. I think this is
due to the amount of light that is able to pass through the objective lenses.
Since the opening of the objective lenses gets increasingly smaller the
higher the power, the amount of light that can pass into the eyepiece
becomes increasingly smaller. The field of vision also succumbs to the
same variables. Due to the amount of light being very small that is able to
pass through the objective lenses, our field of vision is concentrated, and
results in our FOV to become smaller.
8. In order to combat these two situations, the user of the compound
microscope will need to readjust the focus on the microscope, in order to
maintain a good image of the specimen. Also, in order to make sure the
light sent out from the illuminator will be enough to sustain a good/clear
image of the specimen, the user will probably need to push the iris
diaphragm to a higher power. This will make the light brighter to our
eyes, and will create a clear image for the user to see.
9. Under high power one will need to continually adjust the fine focus in
order to see a clear image of the specimen. This is much different
compared to what we would do if we were looking under a low
magnification. If it were under a low magnification, we would mostly use
the course focus to adjust the image to our liking. Also, using high
magnification, we would need the specimen we are attempting to look for
directly in the center of our microscope objective lenses. Otherwise, we
would not be able to see the specimen we are attempting to see.
10. Stereomicroscopes create 3D images to the user, while compound
microscopes only create a 2D image to the user.
11. An electron microscope is a microscope that has an extremely high
magnification and resolution. This microscope uses electron beams to
“view” the specimen, actually hitting the outside of it, to depict an image.
In science, electron microscopes are used to look at the outside of
extremely small objects/living organisms. Light microscopes can only
look at specimens that are very thin, or transparent. Electron microscopes
are also able to create an image that depicts the specimen with colorcoding.
12.
1590 – Zaccharias Janssen and Hans create first compound microscope.
1665 – Robert Hook names the empty chambers he observes in a cork after
magnification “cells”
1674 – Anton can Leeuwenhoek finds microorganisms using a single lens
microscope; also invents new methods of forming better lenses for
clearer magnification
1838 – Matthias Schleiden – Declares that all plants are made of cells
1839 – Theodor Schwann – Declares all animals are made of cells
1855 – Rudolf Virchow – Declares that all pre- existing cells were made from
cells
1903 – Richard Zsigmondy- develops the ultra-microscope, a microscope used
to study specimens under the wavelength of light
1931 – Ernst Ruska invented the electron microscope.
1981 – Gerd Binnig and Heinrich Rohrer invents the scanning tunneling
microscope that produces 3-D images of objects down to the atomic
level
Conclusion:
This microscope activity has taught me many things. I have learned to set
a microscope in order to view and focus on specimens. This allows the user of
the microscope to see the very intricate parts of the specimens. We are also able
to measure the exact parts of the specimens. This lab has been a very interesting
lab, and has taught me many things. The capabilities of each different type of
microscope has also been noticed in our group.